Open mouth bag

ABSTRACT

The invention provides a rigid mouth bag ( 2 ) with a rigid mouth ( 10 ) that places no stress on the bag and which leaves no entrapment areas between the bag and the rigid mouth for product inside the rigid mouth bag to egress into. The rigid mouth is formed as a “Y” joint and the bag inserted between the prongs of the joint. The joint is closed and sealed.

FIELD OF THE INVENTION

[0001] The invention relates to an open mouth bag, and in particular toan open mouth bag including a rigid collar, the collar including a “Y”joint method of closure.

BACKGROUND

[0002] Plastic bags are well known. They can be in the form of flexiblepouches or packaging as disclosed for example in U.S. Pat. Nos.4,286,746, 3,438,567 or 3,318,759. Plastic bags may be attached toframes or handles as for example in U.S. Pat. No. 4,411,300 and EP0 150027.

[0003] Also known are fluid dispensers including collapsible flaccidbags. For example, in U.S. Pat. No. 5,005,733 there is disclosed acollapsible flaccid bag bottle. Integral with the bottle is a thinpassive film that passively manages collapsing of the bottle as fluid isdispensed. U.S. Pat. No. 5,012,956 discloses a fluid dispenser systemwhich is a conventional squeeze bottle within which a collapsibleflaccid bag, containing dispensable fluid, is suspended. U.S. Pat. No.5,004,123 discloses a non-venting fluid dispenser system which has acollapsible flaccid bag loosely suspended in a sleeve and exposed atatmospheric pressure. U.S. Pat. No. 4,147,278 discloses a fluiddispenser in which a second container with a flexible wall is positionedinside a first container.

[0004] In many of the above examples, it is necessary to hold theplastic bag or pouch inside a rigid container. In U.S. Pat. No.4,147,278 this is achieved simply by cuffing back a flaccid bag over theneck of a bottle. The flaccid bag must be attached to a bottle andcannot be used alone. It is prone to leaking. In U.S. Pat. No. 3,420,413the pouch has a moulded in place neck. It is connected to a closure capby sealing rings.

[0005] There is a need for a plastic bag which can be attached to acollar/ring or the like to produce a strong plastic pouch having a rigidopen mouth.

[0006] The rigidly brimmed wide mouth stretch resistant pouch disclosedin U.S. Pat. No. 5,476,322 relates to a pouch having heat sealinglylaminated side margins and a rigidly brimmed wide mouth open end. Thepouch is secured to a rigid annular rim by an open end of the pouchbeing mechanically expanded and tightly contracted over, around andbeneath the rim. The formation of the pouch requires a pouch expander.

[0007] The problem with the pouch of U.S. Pat. No. 5,476,322 is that itdoes not provide a stress-free joint. A weak point of a flexible pouchhaving heat sealingly laminated side margins is the transition edgebetween the heat sealed joint itself and the non-heat sealed pouch wall.When such a pouch is stretched, this directly stresses the weakestportion of the pouch. The plastic bag requires stretching to attach itto the rim.

[0008] Problems with all current methods include:

[0009] i) They have more than two parts, vis-a-vis a rigid mouth, a bag,and a third element such as a heat shrinking band, an external clamp,additional sealing material etc; all these configurations add extra costto the assembly;

[0010] ii) Few rigid mouth bags specifically deal with totally sealingbetween the bag and the rigid mouth. They all try to form a “hermetic”seal, but leave a significant portion of bag/rigid mouth contactunsealed on the inside, ie. they all have product entrapment areas. Thisis due to the severe difficulty in sealing between a rigid mouth and abag when sealing along the open edge surface of a bag.

[0011] In other rigid mouth bag design configurations, this is not aproblem. The best example is the current “wine bag” configuration, wherethe closure is welded on to a flat surface portion of the bag, hencesealing together two totally flat surfaces. A fully sealed joint cantherefore be obtained.

[0012] The problem along an edge surface opening on a bag is caused bytwo factors:

[0013] i) The rigid mouth is generally an injection moulded component(as with the tap assembly in the “wine bag” application), and hence itsdimensional tolerances are quite precise;

[0014] ii) The bag is generally made from a process that does not havesuch fine manufacturing tolerances, ie. folded out of flat sheet into abag through heat sealingly laminated side margins.

[0015] Hence, when the rigid mouth is inserted into the open mouth endof the bag, the fit cannot be perfect. A method of sealing 360° aroundthe joint, without forming any entrapment areas has to be found. Thereare only three possibilities:

[0016] a) The tolerance difference leads to the bag-opening aperturebeing less than the rigid mouth dimensions. In this situation it is nearimpossible to insert the rigid mouth into the bag.

[0017] This is the scenario used in U.S. Pat. No. 5,476,322. Assembly isachieved by stretching the bag over the rigid mouth. As this methodkeeps the bag in tension, it is claimed that this will provide nopossibility of entrapment.

[0018] This results in a permanent stress in the bag.

[0019] b) Both bag aperture and rigid mouth are the same size within afine tolerance.

[0020] This is an extremely low probability, but even if it occurred,one still has a significant problem of how one gets the rigid mouthinserted up inside an extremely tight fit into a very thin-walled bag.

[0021] c) The bag aperture is slightly larger than the rigid mouthdimension. Now one can potentially insert the rigid mouth up into theopen mouth on the bag, but as one tries to seal around the circumferenceof the rigid mouth sealing surface, one ultimately must end up withridges being formed in the bag material (due to the difference insize/circumferences), and these ridges form entrapment areas and canalso lead to complete lack of a hermetic seal.

SUMMARY OF THE INVENTION

[0022] The present invention goes some way in overcoming somedisadvantages with known types of plastic bags. The present inventiongoes some way in providing a substantially rigid open mouth to a bag,whereby the bag is adapted to be automatically inserted into a “Y” jointof a rigid mouth, or which at least provides the public with a usefulchoice.

[0023] Throughout this specification, the term “bag” is intended toinclude pouches, sachets and other similar enclosures.

[0024] In one aspect, the invention provides a rigid mouthed bagcomprising a pouch or the like of flexible material, the pouch beinginserted into a “Y” joint of a substantially rigid mouth, which, uponclosure of the “Y” joint, results in a rigid mouth bag in which nostress is placed on the pouch.

[0025] The substantially rigid open mouth preferably comprises a collaror the like.

[0026] The collar preferably comprises a “Y” joint in its unclosedposition. The pouch is adapted to be inserted between the two prongs ofthe “Y” joint when in its open position and the “Y” joint is then closedto form the rigid mouthed bag.

[0027] Preferably no entrapment areas for product inside the rigid mouthbag are provided.

[0028] The invention also provides a rigid mouthed bag comprising apouch or the like of flexible material, the pouch being inserted into a“Y” joint of a substantially rigid mouth, the “Y” joint comprising twoprongs of substantially equal length, which, upon closure of the “Y”joint results in a rigid mouth bag with no product entrapment areas.

[0029] The invention also provides a rigid mouth bag in constructionfrom a flexible material, the rigid mouth bag including:

[0030] a pouch having an open mouth; and

[0031] a collar, the collar being sealingly connected to the poucharound its open mouth using a “Y3” joint method of closure between themouth and the pouch, thus providing a substantially rigid mouth at theopen end of the pouch, without inducing stress in the bag.

[0032] Preferably the collar is in line with the open end of the pouch.

[0033] The “Y” joint preferably comprises two prongs of substantiallyequal length which, upon closure of the “Y” joint, results in a rigidmouth bag with no product entrapment areas.

[0034] The collar is preferably circular but may be of any requiredshape such as rectangular, or oval.

[0035] The pouch may be constructed of a flexible material and may beeither a single or multi-layer laminate material, preferably a plasticsmaterial.

[0036] The collar may be manufactured from any elastic or semi-elasticmaterial that can be moulded or machined into the specific formrequired.

[0037] The collar may be injection moulded or fabricated out of anextrusion. To manufacture the rigid mouth bag, the pouch may be slid upbetween the prongs of the Y after which the prongs of the Y are closed.

[0038] The invention also provides a method of forming a rigid mouthedbag comprising a pouch or the like of flexible material including thesteps of:

[0039] inserting a pouch of flexible material between the two prongs ofa “Y” joint in a rigid collar;

[0040] closing the prongs of the joint; and

[0041] sealing the joint, to thus produce a rigid mouth bag withoutinducing stress in the bag.

[0042] The invention also provides a method of forming a rigid mouthedbag comprising a pouch or the like of flexible material including thesteps of:

[0043] inserting a pouch of flexible material between two prongs ofequal length of the “Y” joint in a rigid collar;

[0044] closing the prongs of the joint; and

[0045] sealing the joint, to thus produce a rigid mouth bag with noproduct entrapment areas.

[0046] Closure of the Y-joint may be done by a number of mechanisms.Sealing methods include:

[0047] Ultrasonic Welding, either longitudinal welding from the outside,radial welding from the inside, or a combination of both;

[0048] Radio Frequency welding using a radio frequency activated glue inthe joint;

[0049] Gluing;

[0050] Any form of heat sealing process;

[0051] Any form of heat forming process;

[0052] Mechanically “clipping” the Y-joint shut.

[0053] Once the “Y” joint with substantially equal length legs isclosed, the method of securing the “Y” joint, whatever the sealingmethod, provides a complete seal between the pouch and the “Y” joint,leaving no entrapment area for product to egress in to.

[0054] It is not necessary to stretch the bag around the collar or jointand thus a neat, airtight joint may be provided.

[0055] Possible uses of the rigid mouth bag include, but are not limitedto:

[0056] photochemical storage, general laboratory storage, all carbonatedand non-carbonated drinks, powdered drinks, powdered foodstuffs,foodstuffs, paint, domestic and industrial liquids including but notlimited to cleaners and reagents, pharmaceuticals including both liquidand solid forms, as a liner to keep a container clean and reduce theneed to clean containers after use, as a free-standing pouch or as aliner/bladder inside a container, in the medical field as for example acolostomy bag.

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] An embodiment of the invention is now described, by way ofexample only, with reference to the accompanying drawings in which:

[0058]FIG. 1 shows a rigid mouth bag made with heat sealingly laminatedside margins;

[0059]FIG. 2 shows the rigid mouth of FIG. 1 with a blow moulded bag;

[0060]FIG. 3 shows a rigid mouth with symmetrical “Y” joint;

[0061]FIG. 4 shows a rigid mouth with asymmetrical “Y” joint;

[0062]FIG. 5 showing a rigid mouth with asymmetrical “Y” joint andcastellated outer angular leg;

[0063]FIG. 6 shows a joint ready for closure, with internal mouldedfeature;

[0064]FIG. 7 shows a closed “Y” joint;

[0065]FIG. 8 shows a closed “Y” joint with heat forming seal between theouter edge of the inner leg and the inner bag surface lamination.

DETAILED DESCRIPTION OF THE INVENTION

[0066] Referring to FIGS. 1 and 2, a rigid mouth bag is shown generallyat 2. It has a plastic pouch 4 which has an open upper end 6 and asealed lower end 8. The open end 6 is secured to a circular collar 10.The collar 10 is rigid.

[0067] The point of attachment of the pouch 4 to the collar 10 providesa joint 12.

[0068] Referring to FIG. 3, the collar 10 has a Y-joint 12 with prongs12A and 12B. The plastic pouch is slipped up through the prongs 12A and12B of the Y joint 12. The Y-joint is then securely closed. FIG. 3 showsa rigid mouth with a symmetrical “Y” joint.

[0069]FIG. 4 shows a rigid mouth 10 with an asymmetric “Y” joint 13,having prongs 13A and 13B.

[0070]FIG. 5 shows a rigid mouth 10 with an asymmetrical “Y” jointhaving prongs 14A and 14B and an outer angular leg 15 with castellations16.

[0071]FIG. 6 shows a “Y” joint 18 ready for closure. A bag 20 isinserted between the prongs 18A and 18B. A moulded internal feature 22is included.

[0072]FIG. 7 shows a closed “Y” joint 24 with a bag 20 inserted.

[0073]FIG. 8 shows a closed “Y” joint 26 with a heat forming seal 28between the outer edge of the inner leg 26A and the inner bag surfacelamination 30.

[0074] When both “Y” joint legs are of identical length, there will be alack of product entrapment. When one leg is shorter than the other,closing of the “Y” joint will be possible but only a hermetic seal willbe provided. There will still be an entrapment area between the bag andthe longer leg (FIG. 1).

[0075] Referring again to FIGS. 1 and 2, it will be appreciated thatwhen the bag 2 contains a fluid and the bag 2 is turned upside down suchthat the collar 10 is below the pouch 4, the fluid will flow out of theopen end 6. There will be complete removal of the fluid as the rigidmouth bag 2 has no corners to trap remaining fluid.

[0076] Some of the advantages of the present invention are as follows:

[0077] i) It is a cost-effective assembly.

[0078] The joint is only two-piece, a single rigid mouth and a bag.Hence the joint can make a very cost-effective assembly.

[0079] ii) Allows the bag to be automatically inserted into the rigidmouth.

[0080] The “Y” joint format, whether the joint is circular, oval or evenrectangular, allows the bag to be easily slid up into the joint.Typically this is achieved by the combination of a spigot and anassociated expanding mandrel.

[0081] The rigid mouth is placed on the spigot, the mandrel expanded,the bag is then slid up the mandrel creating a sliding guide right up into the “Y” joint, and then the mandrel is retracted.

[0082] The bag is then inserted in its correct position in the “Y”joint. This process can be readily automated. It should also be notedthat this process allows the use of with very thin walled bags.

[0083] The “Y” joint can be a symmetrical “Y” as in FIG. 3, or anyasymmetrical “Y” as in FIG. 4.

[0084] iii) Places no stress on the bag being inserted.

[0085] With the “Y” joint concept, the bag is slid up in to the “Y”joint without stretching or stressing the bag.

[0086] One could argue that a slightly undersized bag opening couldstill slide up inside a symmetrical “Y” joint, and when the joint isclosed, the bag opening would be stretched.

[0087] This is circumvented by the bag opening aperture always beingmade with a positive tolerance, in other words the bag is made using atolerance specification where bags are rejected during manufacture ifthe final opening circumference is under-sized, but accepted if theiropening circumference is within tolerance over-sized.

[0088] iv) Forms a complete seal between the bag and rigid mouth leavingno entrapment areas between the bag and rigid mouth for product toegress in to.

[0089] When the “Y” joint is closed up, the oversized bag does not formridges that can form entrapment areas.

[0090] There are a number of ways to seal closed the “Y” joint, butfirst the “Y” joint has to be physically closed. As mentioned above, nomatter whether the “Y” joint is symmetrical or asymmetrical, bycontrolling the tolerance of the bag during manufacture, the action ofclosing the “Y” joint cannot stretch or “stress” the bag.

[0091] Closing the “Y” joint is a simple mechanical activity, butsealing the joint is not simplistic. As displayed in the attachedFigures, there are a number of possible joint combinations:

[0092] i) The “Y” joint can be symmetrical—FIG. 3 ie. each leg is at thesame but opposite angle out from the centre-line. This configurationsuites highly elastic material, as one leg must compress and one muststretch as the joint is closed.

[0093] ii) The “Y” joint can be asymmetrical—FIG. 4 ie. one leg iseffectively cylindrical while the other leg is at an angle to the centreline. In this case, when the joint is closed the inner cylindrical legneither compresses or expands, while the outer angular leg compresses toform the joint.

[0094] iii) The “Y” joint can be further improved by castellating theangular legs—FIG. 5 shows a cylindrical inner leg and castellatedangular outer leg. In this joint again the inner cylindrical leg neitherexpands nor compresses, while the outer angular legs fold in withoutneed for compression - the castellation slits are designed such thatonce the outer leg has been folded hard against the inner leg, allcastellation slits close up tight. Castellations can be used onsymmetrical or asymmetrical Y joints.

[0095] iv) Any number of other combinations are also possible.

[0096] Once the joint is closed, it has to be sealed. The main points insealing the joint are:

[0097] i) In order to effect a hermetic seal as well as have noentrapment areas, the inner leg must fully seal against the bag innersurface.

[0098] ii) As the inner surface forms the full seal, the outer leg needonly be used for increasing joint strength and for cosmetic purposes to“tidy up” the outside of the joint.

[0099] iii) Because the two legs are of equal length, and once closed,mechanical pressure can be applied to the joint, any ridges formed bythe effective circumference of the bag being greater than the effectivecircumference inside the rigid mouth joint are flattened out leaving nopossibility for entrapment areas.

[0100] iv) As shown in FIG. 6, one can also mould other features in tothe joint, such as raised shoulders or even recesses. These features canhave more than one function:

[0101] a) For ultrasonic welding, the raised shoulder concentrates theultrasonic energy leading to a better welded joint;

[0102] b) Another possible function of the raised shoulder, as well ascorresponding recesses, is to provide additional restraint to stop thebag being pulled out of the joint, hence increasing overall jointstrength.

[0103]FIG. 7 shows a “Y” joint fully closed.

[0104]FIG. 8 shows a “Y” joint fully closed based on the combination ofclosure and sealing techniques used. The points to note about the jointare:

[0105] i) The preferred format is as shown in FIG. 6, with a 360°moulded ridge around the inside of the joint to reduce the potential ofthe bag being pulled out;

[0106] ii) The “Y” joint leg configuration is preferably as shown inFIG. 5, with a cylindrical inner leg and a castellated angular outerleg;

[0107] iii) The joint is mechanically closed, then first ultrasonicallywelded on each castellated joint on the outside. This does not weld theouter leg to the outer surface of the bag, rather it turns thecastellated outer leg into a contiguous 360° band that holds the jointtightly closed and forms a tidy joint on the exterior;

[0108] iv) A heat forming process is then used to physically “melt” partof the inner leg into the bag inner surface right at the transitionbetween the inner leg and bag inner surface. For this situation, the bagis generally a multi-layer laminate.

[0109] This forming can be achieved by either melting part of the leginto the bag surface or by injecting additional molten material intothis region of the joint;

[0110] v) For this style of joint, the rigid mouth material and baginner surface material need to be of similar nature in order for them toeffectively melt together.

[0111] With this joint, it is obvious that, irrespective of any possibleridges formed in the rigid mouth bag as it is sandwiched between the twolegs of the “Y” joint, there is provided:

[0112] 1 A cost effective and tidy joint;

[0113] 2 Good mechanical strength;

[0114] 3 The whole process can be automated;

[0115] 4 The finished joint has no internal product entrapment areas;

[0116] 5 No stress has been induced into the bag.

[0117] It is to be understood that the scope of the invention is notlimited to the described embodiment but that modifications andvariations may be made to the particularly described example withoutdeparting from the scope of the invention as disclosed in thespecification.

Industrial Applicability

[0118] The invention provides a rigid mouth bag with a rigid mouth thatplaces no stress on the bag and which leaves no entrapment areas betweenthe bag and the rigid mouth for product to egress into. The rigid mouthbag comprises a “Y” joint method of closure between the rigid mouth andthe bag. The bag will find uses in numerous fields including, but notlimited to, photography, drinks, foodstuffs, paint, pharmaceuticals,domestic and industrial liquids and as a liner to keep a container cleanand reduce the need to clean containers after use.

1. A rigid mouthed bag comprising a pouch or the like of flexiblematerial, the pouch being inserted into a “Y” joint of a substantiallyrigid mouth, which, upon closure of the “Y” joint results in a rigidmouth bag, wherein the pouch or the like is integrally enclosed withinthe “Y” joint.
 2. A rigid mouthed bag according to claim 1 wherein nostress is placed on the pouch.
 3. A rigid mouthed bag according to claim1 or claim 2, wherein there are no entrapment areas for product insidethe pouch.
 4. A rigid mouthed bag comprising a pouch or the like offlexible material, the pouch being inserted into a “Y” joint of asubstantially rigid mouth, the “Y” joint comprising two prongs ofsubstantially equal length, which, upon closure of the Y joint resultsin a rigid mouth bag in which the pouch or the like is integrallyenclosed within the “Y” joint.
 5. A rigid mouthed bag according to claim4 which comprises no entrapment areas.
 6. A rigid mouth bag according toany preceding claim wherein the Y joint is closed mechanically.
 7. Arigid mouth bag according to any one of claims 1-6 in which the Y jointis sealed after closing.
 8. A rigid mouth bag according to claim 7wherein the sealing method is selected from ultrasonic welding, radiofrequency welding, gluing, heat sealing, heat forming.
 9. A rigid mouthbag according to any one of the preceding claims which is comprised ofonly two pieces: a pouch and a rigid collar.
 10. A rigid mouth bagaccording to any preceding claim in which the rigid mouth is circular,oval or rectangular in shape.
 11. A rigid mouth bag according to any oneof claims 1-8 in which the “Y” joint is symmetrical.
 12. A rigid mouthbag according to any one of claims 1-8 in which the “Y” joint isasymmetrical.
 13. A rigid mouth bag according to any one of claims 1-8or 12 in which the “Y” joint includes a castellated leg, on one or moreangular legs.
 14. A rigid mouth bag constructed from a flexiblematerial, the rigid mouth bag including: a pouch of flexible materialhaving an open mouth; and a collar, the collar being sealingly connectedto the pouch around its open mouth using a “Y” joint method of closurebetween the mouth and the pouch, thus providing a substantially rigidmouth at the open end of the pouch in which the pouch or the like isintegrally enclosed within the “Y” joint.
 15. A rigid mouth bagaccording to claim 14 in which no stress is induced in the bag.
 16. Arigid mouth bag according to claim 14 or claim 15 in which the “Y” jointcomprises two prongs of substantially equal length, which, upon closureof the “Y” joint results in a rigid mouth bag with no product entrapmentareas.
 17. A rigid mouth bag comprising a pouch of flexible material anda collar, the pouch being inserted between two prongs of a “Y” joint inthe collar, the joint being mechanically closed and sealed such that thepouch or the like is integrally enclosed within the “Y” joint.
 18. Arigid mouth bag according to claim 17 in which no stress is placed onthe pouch.
 19. A rigid mouth bag according to claim 17 or claim 18 inwhich the joint is sealed by ultrasonic welding, radio frequencywelding, gluing, heat sealing or heat forming.
 20. A rigid mouth bagaccording to anyone of claims 17-19 in which the inner and/or outer legof the “Y” joint is castellated.
 21. A rigid mouth bag according to anypreceding claim in which the pouch is of a plastics material.
 22. Amethod of forming a rigid mouthed bag comprising a pouch or the like offlexible material including the steps of: inserting a pouch of flexiblematerial between the two prongs of a “Y” joint in a rigid collar;closing the prongs of the joint; and sealing the joint, to thus producea rigid mouth bag in which the pouch is integral with the closed “Y”joint.
 23. A method according to claim 22 in which no stress is inducedin the bag.
 24. A method of forming a rigid mouthed bag comprising apouch or the like of flexible material including the steps of: insertinga pouch of flexible material between two prongs of equal length of the“Y” joint in a rigid collar; closing the prongs of the joint; andsealing the joint, to thus produce a rigid mouth bag in which the pouchis integral with the closed “Y” joint.
 25. A method according to claim24 in which there are no entrapment areas in the bag.